energyi
Posts: 141
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Zero clusters? Pi day deals

Fri Mar 15, 2019 6:23 pm

Anyone done a Pi Zero cluster? Not for power, but to learn/test clusters. Any other good usecase for this?

Yes, addicted to pi. Microcenter deal till the 16 th, less than $11. Zero w, case and 16gig card.

Energyi
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energyi

W. H. Heydt
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Re: Zero clusters? Pi day deals

Fri Mar 15, 2019 6:30 pm

The problem with Microcenter is that they won't sell Pi0s anywhere but in their actual stores. That's great for anyone who lives near one...but they're very thin on the ground.

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thagrol
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Re: Zero clusters? Pi day deals

Fri Mar 15, 2019 7:41 pm

Yes, a cluster of Pi zero has been done. There's even a HAT for it: https://clusterhat.com/
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energyi
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Re: Zero clusters? Pi day deals

Fri Mar 15, 2019 8:50 pm

Thanks thagrol. me gusto mucho.

Usecase for individual low power SBC's clustered such?
energyi

mic_s
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Re: Zero clusters? Pi day deals

Fri Mar 15, 2019 11:29 pm

Example of a super-cheap pi-zero cluster :
viewtopic.php?f=49&t=199994
(and links therein)
Usecase ?
The answer depends on your skills.
For the beginner: GPIO – Expander

For the expirienced :
to learn MPI, to master the 12 SIMD-processing units in every zero of your cluster, to learn openCL … to have fun with your super-cheap pi-zero cluster. .

energyi
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Re: Zero clusters? Pi day deals

Sat Mar 16, 2019 12:25 am

Thanks mic_s, good answer.

energyi
energyi

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Gavinmc42
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Re: Zero clusters? Pi day deals

Sat Mar 16, 2019 12:37 am

Zero's can boot from the USB too, so no need for uSD cards.
See USBboot on the github.

But I'm having to make USB extension cables as I want to use the Cluster for extra displays and need to access the HDMI.
I could not find off the shelf micro USB cable extensions.

"Pi Day" is becoming a thing?
https://www.phoronix.com/scan.php?page= ... iver-Linux
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energyi
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Re: Zero clusters? Pi day deals

Sat Mar 16, 2019 1:02 am

mic_s wrote:
Fri Mar 15, 2019 11:29 pm
Example of a super-cheap pi-zero cluster :
viewtopic.php?f=49&t=199994
(and links therein)
That is one of the most amazing threads I have read on this board, +1 year long and full of great instructions and knowledge by ejolson and others.
" the code developed for the super-cheap cluster will run on a real supercomputer without modification using exactly the same commands."
and
"...our super-cheap cluster has a theoretical peak of 120 single-precision Gflops."

energyi
energyi

energyi
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Re: Zero clusters? Pi day deals

Sun Mar 17, 2019 2:02 am

Is a video wall of multiple HDMI frameless monitors an application for a cluster of pi zeros?
energyi

ejolson
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Re: Zero clusters? Pi day deals

Sun Mar 17, 2019 3:20 am

energyi wrote:
Sat Mar 16, 2019 1:02 am
mic_s wrote:
Fri Mar 15, 2019 11:29 pm
Example of a super-cheap pi-zero cluster :
viewtopic.php?f=49&t=199994
(and links therein)
That is one of the most amazing threads I have read on this board, +1 year long and full of great instructions and knowledge by ejolson and others.
Thanks for the feedback. I think a video wall would be a practical use for a cluster of Pi Zeros, but I've never seen a detailed description of how to set one up.

W. H. Heydt
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Re: Zero clusters? Pi day deals

Sun Mar 17, 2019 3:21 am

energyi wrote:
Sun Mar 17, 2019 2:02 am
Is a video wall of multiple HDMI frameless monitors an application for a cluster of pi zeros?
It was done in the early days of the Pi (hunt back through the blog entries, it was written up there) so Pi0s should be able to do that.

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Gavinmc42
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Re: Zero clusters? Pi day deals

Sun Mar 17, 2019 9:56 am

Is a video wall of multiple HDMI frameless monitors an application for a cluster of pi zeros?
Yep that first video wall had screens of all sorts of weird sizes.
Not sure I think they went and made a display Company from that starting point.
Or were already a display company?

Probably could be recreated if you can get Ethernet gadget mode to work over the USB on the Zero's.
I think Synapse works and VNC etc.
I don't think anyone has yet made a Displaylink client, but there is a driver for it.

I have been messing about with AJ Starks Go OpenVG stuff, he now has some Presentation stuff called Deck.
The Go OpenVG works in Raspbian and Thaddy has done a Free Pascal port of it and there is also an Ultibo baremetal OpenVG version.

Probably a dozen ways to do it now.
Perhaps even via WiFi on the Zero W?
Or Uart or USB to Ethernet Dongle....

Probably best to just follow the Clusterhat instructions :lol:
You could have a HDMI and a DPI LCD display on each Zero, dual display is supported in some modes.
Smaller SPI displays? normally supported for upto 5 SPI LCD's plus HDMI. Bit bang more SPI Chip Selects?
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Raspberries are not Apples or Oranges

ejolson
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Re: Zero clusters? Pi day deals

Sun Mar 17, 2019 5:32 pm

Gavinmc42 wrote:
Sun Mar 17, 2019 9:56 am
Is a video wall of multiple HDMI frameless monitors an application for a cluster of pi zeros?
Yep that first video wall had screens of all sorts of weird sizes.
Not sure I think they went and made a display Company from that starting point.
Or were already a display company?
It seems to me that the main use for video walls is to display giant views of local attractions in airports and randomly changing menus at fast food restaurants also in airports.

Unless you can convince a family-owned restaurant to recreate the same level of customer satisfaction that I feel after finding something that looks like it might be edible only to have it disappear and be replaced by the animation of a coming promotional, then you might have better success marketing yourself as an artist who sets up video walls which display local attractions and upcoming events in visitor centers of smaller townships.

Alternatively, suitable amounts of thick plexiglass could be used to create multipurpose video walls in school cafeterias that function as informational displays about post and upcoming school events during lunch and double as electronic scoreboards for badminton and basketball games the rest of the day.

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Gavinmc42
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Re: Zero clusters? Pi day deals

Mon Mar 18, 2019 1:28 am

Lots of Uni and some schools have displays, these are becoming more interactive.
Museums and even libraries are becoming tech embedded.
The Arduino was invented for Art students.

What happens when you have Zero's with displays and Bluetooth beacons?
Once we have holographic projectors are we in Bladerunner world? :lol:

There are a few good small displays now, Hyperpixel, Manga Screen2, Adafruit 240x240.
If you can find a display that can go as low as 15fps? the Pi's can even do 4K.

I saw a Youtube with a AR display in the wall of a glass bus stop, monsters attacking people, lions on the loose etc.
Changing people perceptions of reality, look for that Landspeeder bike that does it with mirrors.
Do that Topgear invisible car with Pi's?
That will be cool once these large roll up flexible displays are available.
I'm dancing on Rainbows.
Raspberries are not Apples or Oranges

chwe
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Re: Zero clusters? Pi day deals

Mon Mar 18, 2019 2:05 am

hmm if the only reason to build a cluster is cause the bord is on discount.. then.. probably you should save the money.. :D The Zero is probably the worst SBC to build up a cluster.. if you build a display cluster you've to deal with all the mini HDMI and for everything involving calculation power.. The board simply lacks in it.. Maybe with models A.. but even then.. there's more numberscrushing power for the $ on market..
See:
https://www.cnx-software.com/2018/07/10 ... -software/
https://www.cnx-software.com/2017/11/09 ... d-for-220/
https://www.cnx-software.com/2019/01/07 ... rclocking/

if it's about experimenting with a cluster, there are nice solution based on the A64..
https://www.cnx-software.com/2018/02/01 ... on-module/
with a normal network but prewired.. :P

The RPi can be a nice board for various use-cases.. Especially for camera related stuff. But it's not a cluster board..

ejolson
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Re: Zero clusters? Pi day deals

Mon Mar 18, 2019 9:28 am

chwe wrote:
Mon Mar 18, 2019 2:05 am
The Zero is probably the worst SBC to build up a cluster.. if you build a display cluster you've to deal with all the mini HDMI and for everything involving calculation power.. The board simply lacks in it.
In my experience the mini-HDMI port on the Pi Zero works fine with a mini-HDMI cable and mini-HDMI cables cost about the same as standard sized ones.

I found building a cluster using five Pi Zero computers, one Pi B+, a USB hub and a block of wood to work surprisingly well. While the blogs you mention focus on much more capable clusters, it is likely a single PC still performs better.

However, with any type of cluster there is much that can be learned by setting up the system software and writing parallel programs. Moreover, although the network and processors in my super-cheap Pi-Zero cluster are not super fast, the result is a balanced system for which it is possible to write parallel programs that scale in a realistic way with respect to the number of computational nodes used.

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